The primary objective of the experiments outlined in this proposal is to analyze the central representation of the modalities of pain and temperature. Systematic stimulus - response data have been collected from neurons in the spinal cord and are currently being obtained from neurons in the cerebral cortex that are activated by stimulation of high threshold mechanical and low to high threshold thermal receptors. Concurrent anatomical studies have analyzed the connections to and from regions of the thalamus associated with terminal projection from the spinothalamic tract. BIBLIOGRAPHIC REFERENCES: Burton, H. and Bunge, R.P. 1975 A comparison of the uptake and release of H3-norepinephrine in rat autonomic and sensory ganglia in tissue culture. Brain Research, 97: 157-162. Burton, H. 1975 Responses of spinal cord neurons to systematic changes in hindlimb skin temperatures in cats and primates. J. Neurophysiol. 38: 1060-1079.